Tag Archives: blue whale

How blue whales use their memory to find food

Blue whales eat krill — a lot of it, as it’s not easy to power a basketball-court-sized animal weighing as much as 25 elephants. It is estimated to take 2,200 pounds (1 metric ton) of food to fill a blue whale’s stomach, and during peak consumption periods, they can devour up to 8,000 pounds (3.6 tons) in a single day.

Now scientists have found how they know where to get it.

Blue whale in the Arctic waters — probably looking for some krill to eat. Image credits: AWeith.

Government and university researchers have been examining records of both whale migration and oceanic conditions in the California Current Ecosystem — a coastal upwelling biome, one of the richest and most productive marine ecosystems. Researchers found that blue whales almost perfectly match the timing of their migration to the historical average timing of krill production, rather than matching the waves of krill availability in any given year. The study, which was published in the Proceedings of the National Academy of Sciences (PNAS), found that blue whales rely heavily on their memory in making these movement decisions.

The team used a decade’s worth of tagging data from the Marine Mammal Institute at Oregon State University to determine daily blue whale movements of 60 individual whales. They then compared that with satellite-based measurements of ocean productivity.

There are an estimated 10,000 blue whales in the world, and a quarter of them spend time in the waters off the west coast of the Americas. They travel from the Gulf of Alaska all the way down to an area near the equator known as the Costa Rica Dome. This range makes them quite vulnerable in the face of commercial ships, and it’s unclear exactly just how they came to use these migration routes.

“We think that blue whales have evolved to use historical migration routes and timing that put them in proximity to the most predictably high production feeding areas and then make minor adjustments based on local conditions,” said Daniel Palacios, a principal investigator with Oregon State’s Marine Mammal Institute and a co-author on the study.

“There are various time scales of events that could change the timing of phytoplankton blooms – and thus the availability of the whales’s preferred prey, krill”, he noted, “including La Nina and El Nino events and the Pacific Decadal Oscillation. But the whales’ strategy of relying on memory and historic timing at least gets them into the ‘Goldilocks zone'”.

The study is one of the first to determine how, precisely, ocean life tracks their food. Like whales, countless land species might migrate long distances for their meals. Unlike whales, those species adjust their courses to find the food. Whales, it seems, just go back to the same grocery they went to before.

“We know that many species that migrate on land, from caribou in the Arctic to wildebeests in the Serengeti, enhance their survival by carefully adjusting the pace and timing of their migrations to find food as it becomes seasonally available along the way, rather than just migrating to get from point A to point B,” said Briana Abrahms, a research ecologist with the NOAA Southwest Fisheries Science Center in Monterey, CA, and lead author on the study.

The blue whale is the largest known creature to ever inhabit the Earth but up until very recently, almost nothing was known about its mating and migration routes. Oregon State’s Bruce Mate changed all that, leading a series of tracking studies, but our understanding of blue whale ecology is still quite low. An extra incentive to study them now is climate change. Whales might find it difficult to adapt to ecosystem changes that result from it, said Abrahms.

“With climate change, we’re seeing deviations from those averages that are far outside of the normal ranges of variability,” she said. “It raises concern that the magnitude of change is happening far more quickly than what whales or other animals ever had to adapt to before. We still have a lot to learn about how large animals navigate in the ocean, how they find good habitat and how they are affected by human activities and environmental changes.”

Understanding how blue whales make movement decisions give scientists insight into how whales may, or may not, be able to cope with changing ocean conditions in the future.

Journal Reference: Abrams et al. Memory and resource tracking drive blue whale migrations. Proceedings of the National Academy of Sciences, 2019; 201819031 DOI: 10.1073/pnas.1819031116

Blue Whale Interrupts TV Host Talking About How Hard it Is to Find Blue Whales

Spotting wildlife, especially species as elusive as the blue whale, can be extremely time consuming and at times frustrating. But every once in a while, you get a streak of luck, as Zoologist Mark Carwardine just did. He was explaining why spotting blue whales is so difficult, when suddenly… a blue whale appeared!

Blue whales are marine mammals, and they’re the larger species ever known on Earth. They were abundant in all the Earth’s oceans until the 20th century, when they were almost hunted to extinction by whalers. A 2002 report estimated there were 5,000 to 12,000 blue whales worldwide.

An adult blue whale. Image via Wikipedia.

This clip was taken from Big Blue Live, a new live series coming soon to BBC One in the UK and PBS in the US.

Left, a fin whale after lunging; right, anatomy of the new sensory organ, responsible for coordinating the biomechanics of their extreme lunge-feeding strategy. Illustration by Carl Buell, arranged by Nicholas D. Pyenson / Smithsonian Institution.

New vital feeding sensory organ discovered in Rorqual whales

A group of researchers at University of British Columbia and the Smithsonian Institution have discovered a new sensory organ in rorqual whales, a subspecies of  baleen whales, which also includes the largest animal that has ever lived, the blue whale, capable of reaching 150 tonnes. The scientists involved in the study claim that this organ plays a vital role in the Rorqual whales signature lunge-feeding behaviour, responsible for their enormous size.

Rorqual whales include blue, fin, minke, and humpback whales and are notoriously known for their enormous size, but also for their melodic, haunting calls, whose sounds can travel across thousands of miles in the ocean. Their main physiological characteristic is a special, accordion-like blubber layer that goes from the snout to the navel. This blubber can expand several sizes its resting size during feeding, during which massive quantities of prey-filled water to be swallowed and then expelled back out while filtering the prey.

Scientists collected samples from recently deceased  fin and minke whale carcasses captured as part of Icelandic commercial whaling operations, and scanned them. A three dimensional map of the internal structure of whale tissues, revealed a grape fruit-sized sensory organ, located between the tips of the jaws, and supplied by neurovascular tissue.

“We think this sensory organ sends information to the brain in order to coordinate the complex mechanism of lunge-feeding, which involves rotating the jaws, inverting the tongue and expanding the throat pleats and blubber layer,” says lead author Nick Pyenson, a paleobiologist at the Smithsonian Institution, who conducted the study while a postdoctoral fellow at UBC. “It probably helps rorquals feel prey density when initiating a lunge.”

A fin whale, the second longest whale on the planet, can engulf as much as 80 cubic metres of water and prey – equal or greater than the size of the whale itself – in each gulp in less than six seconds.

Left, a fin whale after lunging; right, anatomy of the new sensory organ,  responsible for coordinating the biomechanics of their extreme lunge-feeding strategy. Illustration by Carl Buell, arranged by Nicholas D. Pyenson / Smithsonian Institution.

Left, a fin whale after lunging; right, anatomy of the new sensory organ, responsible for coordinating the biomechanics of their extreme lunge-feeding strategy. Illustration by Carl Buell, arranged by Nicholas D. Pyenson / Smithsonian Institution.

“In terms of evolution, the innovation of this sensory organ has a fundamental role in one of the most extreme feeding methods of aquatic creatures,” says co-author and UBC Zoology Prof. Bob Shadwick.

“Because the physical features required to carry out lunge-feeding evolved before the extremely large body sizes observed in today’s rorquals, it’s likely that this sensory organ – and its role in coordinating successful lunging – is responsible for rorquals claiming the largest-animals-on-earth status,” Shadwick adds.

“This also demonstrates how poorly we understand the basic functions of these top predators of the ocean and underlines the importance for biodiversity conservation.”

The findings were reported in the journal Nature.

Source: University of British Columbia via Planet Save.

Animals all over the world against noise pollution

A magnificent blue whale

Pollution can take numerous and unexpected shapes; one of the not-so-deadly, but still extremely unpleasant types is noise pollution. You probably don’t notice it because it’s so common, but it’s a really noisy world out there; if for a few days you were to go somewhere far away from all the fuss and noise that affect us on a daily basis, you will probably have a hard day when you come back, before you get used to all the sounds again.

The world's shipping routes. Credit: National Center for Ecological Analysis and Synthesis.

It is true that all environments have some kind of ambiental noise, caused by rivers, waves, other animals, wind, etc, but we humans have drastically increased the amounts of daily decibels out there. Basically, on land we’re dealing with cars, airports, machinery, and in the sea the problem is mostly caused by shipping, but also deep water drilling, explosions, etc. This may not seem like a big issue, but when some of the most important things in your life, like hunting and mating, are determined by sounds, you definitely have a problem on your hands.

Animals have always had ways to deal with the sounds; when it comes to short term ones, such as wind or rain; most just wait until it stops and then continue their activity. Tawny owls, for example, stop calling each other, and bushcrickets delay their nocturnal symphonies until morning when there are other noisy insects around. But anthropic noises are not short term, and humans have always been remarkably good at making noise.

Tawny Owl

The next usual approach animals take is being even louder than before. It’s something natural, everybody does it all the time (even though it’s not really a good idea, for example when your mother or daughter is screaming at you). But this comes at a cost; have you ever been to a really good concert ? If you have, the odds are you’ve come home with a really sore throat caused by screaming. This phenomenon was first described by Etienne Lombard 100 years ago, and since then, it has been used to describe the increase in amplitude of a vocalization.

Research upon Great tits, Beluga whales, orcas, manatees and numerous other species has shown that this effect can be quite common – especially as it requires quite some effort to scream all the time. This may be what causes blue whales to sing lower and lower every year, but there still is a lot we have yet to understand about the changes species undergo from loud noises.

However, one thing is loud and clear – the sounds we make have a definite impact on animals, and many of them are out there right now, screaming “Can you hear me?” louder and louder every day. Surprisingly, the answer is no.

Source

Whales suffer from sun burns too

You know those days when you go to the beach, and it’s just too hot outside, so you have to use some cream and all ? Well, it’s a little harder if you’re a whale. A recent study conducted that a whole lot of whales displayed blisters caused by sun damage.

Laura Martinez-Levasseur, from the Zoological Society of London (ZSL) and Queen Mary, University of London studied more than 150 whales from the Gulf of California, by taking pictures as well as skin samples; she explained that whales are a good model for studying marine animals, because “they need to come to the surface to breathe air, to socialise and to feed their young, meaning that they are frequently exposed to the full force of the sun”.

Examining the high res pictures they located the blisters and then put the skin samples under the microscope. The results were conclusive: the blisters were caused by sun burns. They also found something else, that paler coloured whales are more exposed to this kind of damage. Darker whales have more cells that produce a dark pigment called melanin. In humans, this is the result of a slight DNA altering caused by sun burn, and all signs seem to indicate the same thing in other mammals.

“This is the first evidence that the Sun’s rays can cause skin lesions in whales,” said Ms Martinez-Levasseur.
“The increase in skin damage seen in blue whales is a matter of concern, but at this stage it is not clear what is causing this increase. A likely candidate is rising ultraviolet radiation as a result of either ozone depletion, or a change in the level of cloud cover.”

The similarities to humans don’t stop here though. Professor Edel O’Toole, a skin specialist also involved in the study said:

“As we expect to see in humans, the whale species that spent more time in the sun suffered greater sun damage. We predict that whales will experience more severe sun damage if ultraviolet radiation continues to increase.”

The study showed no signs of skin cancer, but research is still going on. Other marine animals are also exposed to this kind of burns, especially hairless animals, like dolphins for example. The damage is also more serious in the areas with more ozone depletion, especially in the poles.

Blue whales singing lower every year, baffled scientists say

Blue whales are not only the biggest living creatures in the world right now, but the biggest ever to have ‘walked’ the face of the earth; they’re also the loudest for that matter. After recovering from near extinction in the beginning of the 20th century, blue whales are finally getting a part of the respect they deserve.

However, researchers cannot understand what is causing these majestic creatures to ‘sing’ at lower frequencies year after year. No one is fully sure of all the uses of the blue whale songs, but it’s known they are used to communicate and as a mating ritual. However, ever since the 1960s, the frequencies which these giants use are getting lower and lower, without anybody being able to give an explanation.

full_bluewhale_6

Of course, some theories have emerged, the two most likely being that it’s a direct result of the water pollution or a sign that an almost extinct population is recovering. Mark McDonald, president of Whale Acoustics, a company that specializes in recording the songs of blue whales (yeah, really) originally thought the cause could be noise pollution caused by intensified traffic; however, if this would be the case and they would want to make themselves heard louder, they would use higher, and not lower frequencies. This may be a bit weird because generally lower frequency transmissions are used for long distances, but mister McDonald explains:

Across the frequencies of blue whale song, the underwater transmission losses are nearly the same regardless of frequency. It is absorption which is the primary cause of frequency dependent transmission losses, rather than dispersion in this case, and the absorption loss only begins to become significant when ranges reach thousands of kilometers. Theory tells us the whales can produce higher amplitude songs at higher frequencies, based on given lung volume.

whales

Another possible reason could be a change in the mating rituals. Scientists have long known that only male blue whales sing, and larger (which are usually more mature) specimens sing at lower frequencies. The hypothesis is that the younger guys are trying to emulate the older ones in order to attract females (that seems familiar). Either way, there are many we have yet to understand about the way these marine mammals act. The only good thing is that the blue whale populations is nearing a normal limit; let’s set this as an example for other species too, instead of treating them with less care now that they’re not on the brink of extinction anymore.

6 record holding animals you’ll never be as good as

animal

Photo by bocavermelha
Sometimes, animals are better than humans. Quite a lot of times actually, but that’s not the point here. We’re going to take a look at some record holding animals that are (or do things that are) just unbelievable!

  • The biggest – the blue whale.

animal

Photo by Dan Shapiro. Credit: NOAA via pingnews

It’s the biggest creature to have ever walked the face of the earth. Mature blue whales can measure anywhere from 75 feet (23 m) to 100 feet (30.5 m) and they weigh just about 150 tons (how do you weigh them?). Also, the blue whale holds another record – perhaps even a more spectacular one: it has the biggest penis. Yeah, and it goes up to 3-4 meters. that’s almost twice as tall as you. The tallest man to ever live (which by the way, is way above the average) was 2.72 m.

  • The fastest (3 categories) – cheetah, peregrine falcon and sailfish

animal

Photo by tinyfishy

Obviously, there’s no point in comparing land creatures with air ones, or water. So let’s just make three categories, with a winner each. I think they’ll settle with a share of the spoils. So, the cheetah can reach 70 mph for short distances, which is about as much as the sailfish goes. But, that’s not it; peregrine falcons fly at 90 mph and dive at 200 mph. Not much of a chance for you if you’re a fish. For a comparison, the world record for 100 meters is just under 10 seconds, which means a speed of about 22 mph.

  • The animal that lives in the deepest parts of the ocean – undecided

animal

Photo by nalina asha

Yep, we have an undecided event. That’s because it’s really hard for us to explore those extreme places and we haven’t been everywhere yet. Also, probably the creatures that live in the deepest parts are microorganisms. Anyway, sincer we don’t have a winner… the viper fish looks pretty great and it lives in really deep environments, so let’s say some things about it: it’s really easy to recognize due to the large mouth, long fang-like teeth and long first dorsal fin ray (up to half the body length). Extreme environments give fish extreme traits, such as chemical processes that create light. They’ve been known to live more than 2500 meters below the surface, where the pressure is equivalent to about several tens of jumbo jets lying on top of each other.

  • The most powerful – rhinoceros beetle

animal

Photo by artour

Actually, this is about proportional strength: this little beetle that can fit in the palm of your hand can lift about 850 times its own weight. For a human, that would mean lifting about 60 tons (maybe on a good day, after a good workout). It uses it’s horn much in the way that a rhino does, and scientists believe the beetle has become so strong in order to dig safely to the surface.

  • Oldest living creature – bacteria

So you were expecting turtles, maybe elephants? Perhaps a plant, for cryin’ out loud! Betcha you can’t guess how old this bacteria is. Scientists can’t either. But what they can, is approximate; and they approximated the age of a bacteria found in ancient sea salt beneath Carlsbad, New Mexico to 250 million years! They were able to revive it from a state of suspended animation. The species hasn’t been even identified yet. Also, the oldest macroscopic organism is believed to be King’s Holly (Lomatia tasmanica) – found in the rainforests of Tasmania – 43.000 years old ! Lomatia is triploid, that is, it has three sets of chromosomes instead of two. Because of this it is unable to sexually reproduce. The clonal thickets reproduce vegetatively by root suckering.

  • Loudest animal – blue whale

animal

Photo by ocean.
The blue whale can make sounds of almost 190 decibels. Doesn’t sound like much to you? To give you an idea, a man can not scream over 70 db and the loudest rock concerts rarely go near 150 db. But the bad thing is the fact that these just fantastic creatures are endangered – they’ve been so since the 1960s. Their numbers have decreased to less than 10.000, but hopefully they will be able to recored and strive once again – they’ve earned it.